Ball joints allow pivoting movement of automotive suspension or steering components relative to each other while retaining the capacity to transmit axial and shear forces thereby accommodating wheel movement, steering movement, stability and wheel alignment. Ball joints include a stud with a shank that is typically threaded at one end for releasably connecting to an adjacent component. Other types of connections between the stud and component are also used. The stud has a spherical ball at the opposite end mounted within spherical bearings housed in a ball joint housing. Wear between the ball end and bearings is reduced by use of fluid lubricants.
A flexible rubber boot is resiliently sealed with a sliding seal to the outer surface of the stud shank and a base of the flexible boot is sealed and secured to the outer surface of the housing, to prevent contamination of the lubricant and contact surfaces by abrasive particles, moisture or chemicals like salt, and the accompanying abrasive wear, lubricant degradation and metal corrosion. The protective rubber boot holds the lubricant within the boot interior and the boot seals prevent contaminants from contacting the moving parts and lubricant within. Common means of mounting the base of a “press-in” flexible boot to the housing is to press, stretch and slide the boot base over the exterior of the rigid cylindrical housing. A press-in boot base is conventionally secured using a recessed groove in the housing, a spiral ring clip contracting the exterior of flexible boot around the exterior of the boot base, a resilient metal ring clip embedded in the rubber boot base, or a combination of these elements.
Such flexible boots can be easily removed since the retaining ring clips remain flexible and during heavy use the seal between the base of the boot and the housing can be damaged or unintentionally loosened thereby allowing penetration of contaminants into the lubricant and into contact with the bearings, ball end and other interior parts of the ball joint. Once contaminants such as abrasive particles, salt, moisture or chemicals are present within the interior of the ball joint, wear and corrosion are accelerated and the useful service life of the ball joint is reduced significantly.
Ball joints are mounted to adjacent automotive suspension, stabilization and steering components by mechanical press fitting or threading the cylindrical housing of the ball joint into a matching through hole in the component. For example ball joints are mounted to upper and lower control arms in wheel suspension systems, mounted at both ends of a stabilizer link, mounted to stabilizer bars and mounted in steering linkages.
A through hole is cast or forged, reamed, drilled or machined into the automotive component to match the exterior cylindrical surface of the ball joint housing. The housing often includes a laterally extending flange to abut the surface on the side of the component through which the ball joint is inserted. Once the housing is press fit or threaded and securely seated with the flange against the component surface, a resilient retention ring clip is mounted into a matching groove in the exterior of the housing.
The retention ring clip together with the flange secures the housing on opposite sides of the automotive component to limit relative axial movement. In the event that the press fit or threading connection fails, the retention ring clip provides a safety back-up system to prevent the ball joint and component from separating axially. Catastrophic failure and loss of vehicle control could occur if the ball joint housing becomes axially dislodged from the automotive component, particularly critical steering or suspension components.
The retention ring clip is often spaced an axial distance from the adjacent surface of the automotive component to allow access with tools and aid in installation. When dislodgement occurs, the axial distance between the retention ring clip and automotive component causes significant rattling noise, fretting and impact damage that further reduces the useful service life of the ball joint. A tight engagement between the retention ring clip and component surface would interfere with inserting the points of locking snap-ring pliers or other tools into matching holes in the ends of C-shaped retention ring clips during installation and manufacture.
Therefore some degree of gap is provided for tool access despite the possibility of rattling when the housing is dislodged, since the retention ring clip may be considered to be an emergency or seldom required back up safety measure to prevent catastrophic failure. Any rattling may be considered to be an audible warning that something is out of place or damaged in the suspension or steering system which requires investigation by a mechanic before a major failure occurs.
It is desirable to provide an improved connection between the ball joint housing and the automotive component, an improved connection between the ball joint housing and the flexible protective boot, and to simplify manufacture, installation and maintenance of auto motive ball joints.
Features that distinguish the present invention from the background art will be apparent from review of the disclosure, drawings and description of the invention presented below.